Spin logic enabled by current vector adder

In order to advance the silicon integrated circuit technology, researchers have been searching for memory and logic devices with new physical state variables other than charge. Spin logic device that adds one degree of freedom-electron spin to charge has been considered as a promising candidate due to its low power consumption, built-in memory, and high scalability. Here, we demonstrate that a new variable – current direction on the sample can be introduced into the spin logic operation. The current direction of the sample is considered as a vector. For the various input currents along different directions, the direction of vector sum (vector adder) determines the output and therefore can enable complex logic functions. We have realized the basic Boolean logic gates including AND, OR, NAND, NOR, and even complicated IMPLY in a single device and further constructed a full adder with only 2 devices. By increasing the number of degrees of freedom one can reduce overall number of devices required to perform logic operations. Here, Zhao, Zheng, Wang et al demonstrate a device using current direction, a vector property, allowing for the implementation of Boolean logic, including IMPLY in a single device, and further enabling the construction of a full adder with only two devices.